KR20150130057A - Apparatus for measuring biological signal - Google Patents

Abstract

The present invention relates to an apparatus for measuring a bio-signal which corrects a signal even when an impedance imbalance between electrodes occurs, and accurately extracts a waveform of the bio-signal in which a common mode noise is removed. The apparatus for measuring a bio-signal comprises: two channels which detect biopotential of a body with two electrodes (10, 20) individually; a bio-signal extraction unit (100) which amplifies the individual biopotential inputted by the two channels with an amplifier, and differentially calculates the biopotential with a differential calculator to obtain the bio-signal where the common mode noise is restrained; and an impedance correction means (200) which restrains the common mode noise caused by the impedance imbalance between the channels by controlling an amplification degree of the amplifier so as to decrease the power of the common mode noise blended in the bio-signal obtained in the bio-signal extraction unit (100).

Description

[0001] APPARATUS FOR MEASURING BIOLOGICAL SIGNAL [0002]

The present invention relates to a bio-signal measuring device for accurately extracting a bio-signal waveform in which a signal-to-noise is suppressed by correcting a signal even if an impedance imbalance occurs between electrodes.

Biological signals are minute electrical signals generated between cells of a human body. They are used to judge the state of the patient and the current state of the patient in the medical field. Typical examples include ECG, EMG, and EEG.

1, which is an example of an electrocardiogram measuring apparatus, includes two electrodes 10 and 20 for detecting a living body in contact with a specific part of a human body in which a living body signal is sensed, A bio-signal extracting unit 40 for receiving the bio-potential signal through differential conductors 11 and 21 connected to the bio-signal extracting units 10 and 20 to obtain a bio-signal, And a signal processing unit 50 for wired transmission. 1 includes a commonly used right leg driving circuit 60 and a reference electrode 30 which contacts a specific part of a human body in addition to an electrode for detecting a living body potential. The electrocardiogram measuring device shown in Fig. Extracts the in-phase noise from the extracting unit 40, amplifies the in-phase noise by the inverting amplifier Gr, and applies the same to the reference electrode 30 through the lead.

Here, the bio-potential signal measured by the two channels through the two electrodes 10 and 20 is a form in which a minute bio-signal and a relatively large external common-mode noise signal are combined. Since the external noise signal is detected simultaneously by the two electrodes 10 and 20 as the in-phase, it can be suppressed by the differential operation of the biological signal extraction unit 40 to acquire the biological signal.

In Korea, for example, a commercial electric wave is a 60 Hz noise signal because the commercial electric wave is a 60 Hz frequency. In Europe, a 50 Hz noise signal is a commercial electric wave having a frequency of 50 Hz.

1 shows only one pair of unit measuring devices constituted by two electrodes 10 and 20, it is also possible to connect a plurality of unit measuring devices to a multiplexer (MUX) to selectively connect the specific unit measuring device to the bio- ). In addition, as disclosed in Japanese Patent Application Laid-Open No. 10-2012-0102444, it is also possible to use a plurality of unit measuring devices to extract biological signals.

However, if the impedance between the electrode and the human body varies and a difference in impedance occurs between the two electrodes, a substantially same phase noise that is larger than the biological signal to be measured is not suppressed by the differential calculation of the bio- Issue issues. That is, if impedance imbalance occurs between the two electrodes, the in-phase noise signal, which is much larger than the living body signal, is not sufficiently suppressed by the differential calculation and remains as a very large signal.

In order to solve such a problem, Japanese Patent Registration No. 10-0868071 discloses a method of monitoring the impedance of an electrode to detect the impedance imbalance of the electrode.

Impedance unbalance can occur instantaneously due to the movement of the human body. When the electrode is attached to the human body using the electrolyte gel, the impedance unbalance due to the difference in hardening of the electrolyte gel may occur. When the impedance unbalance occurs, Is a problem that can be cumbersome and inaccurate.

EN 10-0868071 B1 2008.11.04. KR 10-2012-0102444 A Sep 18, 2012.

Accordingly, the present invention was made to solve the problem of impedance unbalance of electrodes which may vary occasionally. Even if impedance unbalance between electrodes occurs, signal processing of the bio-signals detected by the electrodes is performed, The present invention has been made in view of the above problems, and it is an object of the present invention to provide a bio-signal measuring device which suppresses a problem caused by impedance imbalance.

In order to achieve the above object, the present invention provides a living body signal measuring apparatus comprising: two channels for detecting a living body potential of each human body by two electrodes (10, 20); A bio-signal extracting unit (100) for acquiring a bio-signal by amplifying the bio-potentials input through the two channels by an amplifier and performing differential operation with a differential operator to suppress the in-phase noise; And impedance correction means (200) for adjusting the amplification degree of the amplifier so as to reduce the power of the in-phase noise mixed in the bio-signal acquired by the bio-signal extracting unit (100), thereby suppressing the in- .

The impedance correcting means 200 increases the amplification of one of the two amplifiers provided for each channel to the bio-signal extracting unit 100 and reduces the amplification of the other amplifying unit, And the amplification degree of the amplifier is tracked and adjusted so that the power of the common mode noise mixed in the bio-signal becomes small.

The biometric signal extracting unit 100 is provided in two and connected in parallel to the channel, and the impedance correcting means 200 adjusts the amplification degree of one of the biometric signal extracting units to reduce the common noise of the other biometric signal extracting units The process of adjusting the amplification degree of the other biological signal extracting unit while repeating the process of adjusting the amplification degree of the other biological signal extracting unit by repeating the amplification of the amplifying degree of the other biological signal extracting unit, And adopts a bio-signal acquired from the bio-signal extracting unit.

When the in-phase noise becomes smaller than that of the other biometric signal extracting unit by adjusting the amplification degree of the biometric signal extracting unit, the impedance correcting unit 200 corrects the amplification degree of the other biometric signal extracting unit After the adjustment of the adjusted amplification degree, the amplification of the amplification factor of the other biological signal extraction unit starts to be changed.

The in-phase noise signal is obtained by summing the signals amplified by the two amplifiers included in the bio-signal extracting unit 100 to obtain the in-phase noise signal. The in- And residual noise removing means (300) for subtracting the signal obtained by the biological signal extracting unit (100) from the signal obtained by normalizing the signal with the power of the noise to acquire a biological signal suppressing residual common mode noise .

The residual noise removing unit 300 multiplies the in-phase noise signal by the ratio of the in-phase noise power of the signal obtained by performing the differential operation on the power of the obtained in-phase noise signal to the bio-signal extracting unit 100 to perform normalization .

The residual noise canceling means 300 is operated after the operation of the impedance correcting means 200 to suppress the residual common mode noises after suppressing the common mode noise due to the impedance unbalance between the channels.

The impedance correcting means 200 tracks and adjusts the amplification degree of the amplifier so that the power of the commercial electrical frequency component becomes smaller in the signal acquired by the bio-signal extracting unit 100, and the residual noise removing unit 300 normalizes Is a ratio of the power to the commercial electric frequency component.

The impedance correcting unit 200 applies a signal of a predetermined frequency band to a signal obtained by the bio-signal extracting unit 100, And the ratio of power for normalization in the residual noise canceling unit 300 is a ratio of power to the preset frequency band component.

The impedance correcting means 200 corrects the signal obtained by the bio-signal extracting unit 100 and the predetermined signal to be applied to the human body through the electrode The ratio of the power for normalization in the residual noise canceling means 300 to the signal of the specific pattern to be applied to the human body, .

The bio-signal extracting unit 100 includes two preprocessing units 110 and 120 for amplifying a bio-potential signal input through two channels by amplifiers and then performing differential computation on the bio-signal by differential amplifiers, (+) Input terminal of either one of the preprocessing units, and the (-) input terminal of the other of the preprocessing units. The signals obtained by the two preprocessing units (110, 120) The impedance correcting unit 200 extracts the in-phase noise power mixed with the bio-signal acquired by the differential arithmetic unit 130, and outputs the in-phase noise power to the second arithmetic unit 130. The in- And controls amplification of the amplifiers provided for the respective channels in the preprocessing units 110 and 120 of the tanks.

The differential operation unit 130 extracts the in-phase noise power from the signals obtained by the two sets of preprocessing units 110 and 120 so that the same phase noise power is mixed with the signals obtained by the two sets of preprocessing units 110 and 120 And then the differential signal is obtained by performing differential calculation after normalization.

The impedance correcting means 200 may preliminarily designate one of the input terminal polarities of the pre-processing units 110 and 120 to control the amplification degree of the amplifiers provided in the two sets of preprocessing units 110 and 120 The amplification degree of the amplifier connected to the input terminal of the specified polarity is made larger than the amplification degree of the amplifier connected to the input terminal of the other polarity.

According to the present invention configured as described above, amplifiers are provided in two channels that receive a living body potential through two electrodes, and the amplification degree of the amplifier is adjusted so that the power of the common mode noise signal is reduced. Thus, It is possible to obtain a biological signal suppressing the common-mode noise even if an impedance imbalance occurs between the two.

In addition, the present invention eliminates the impedance imbalance by adjusting the impedance of the channel when the impedance imbalance between the channels occurs, and by performing the amplification operation using the amplifier before the differential operation, Even if the impedance of the channel fluctuates instantaneously due to the motion of the human body during the measurement, the biological signal of the correct waveform can be obtained quickly in response to the fluctuation of the impedance of the channel.

Further, according to the present invention, even if the common-mode noise is suppressed by using the amplifier, the remaining common noise suppressed by the residual noise canceling means can obtain a more accurate living body signal.

1 is a configuration diagram of a conventional bio-signal measuring apparatus.
2 is a configuration diagram of a bio-signal measuring apparatus according to a first embodiment of the present invention;
3 is a detailed configuration diagram of Fig.
FIG. 4 is a detailed configuration diagram of a living body signal measuring apparatus according to a second embodiment of the present invention; FIG.
5 is a detailed block diagram of a bio-signal measuring device according to a third embodiment of the present invention;
6 is a detailed configuration diagram of a bio-signal measuring device according to a fourth embodiment of the present invention;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

2 is a configuration diagram of a bio-signal measuring apparatus according to a first embodiment of the present invention.

Referring to FIG. 2, the bio-signal measuring apparatus according to the first embodiment of the present invention includes at least two or more than two bio-signals detecting units for detecting bio-potentials appearing on the skin of a human body at different specific regions designated according to the types of bio- A plurality of electrodes (10, 20); A biological signal extracting unit (100) for calculating a biological potential to be detected by two electrodes selected from a plurality of electrodes to obtain a biological signal suppressing in-phase noise; And a signal processing unit (50) configured to store, analyze, wire transmit or wireless transmit the acquired bio signal,

Two amplifiers G11 and G12 provided in the bio-signal extracting unit 100 to amplify the bioelectrical potentials input to the two electrodes and then to perform differential calculation; An impedance correction means 200 for adjusting the amplification degree of the amplifier so that the power of the residual common mode noise signal mixed with the bio-signal acquired by the bio-signal extraction unit 100 is reduced; Residual noise removing means 300 for further suppressing and transmitting the same phase noise remaining in the bio-signal acquired by the bio-signal extracting section 100 to the signal processing section 50 even if the impedance correcting means 200 suppresses the same phase noise; .

The plurality of electrodes 10 and 20 are generally of a contact type which are directly attached to the skin of the human body and are electrically connected to the bio-signal extracting unit 100 by the conductors 11 and 21. Although only two electrodes 10 and 20 are shown in the figure, in the embodiment, three or more electrodes are often used to measure EMG, electrocardiogram, or EEG.

In the case where there are two or more electrodes, it is possible to selectively connect an arbitrary electrode to the bio-signal extracting unit 100 by using a multiplexer (MUX) or a switch, The multi-electrode signals may be simultaneously measured, and the shape of the multi-electrode signals may vary depending on a bio-signal measurement application.

As shown in FIG. 2, a right-leg driving circuit 60 is provided for extracting the in-phase noise from the bio-signal extracting unit 100 and inverting and amplifying the noise signal Vs appearing as in-phase noise on the skin of the human body A signal obtained by inverting and amplifying the in-phase noise through the reference electrode 30 connected to the lead 31 can be fed back to the human body.

The signal processing unit 50 may be modified in various ways according to the installation method of the bio-signal measuring device (for example, a body wearing method) or the purpose of use.

These electrodes 10, 20 and 30, the right leg drive circuit 60 and the signal processing section 50 are well known techniques. In the case of the noise signal Vs, for example, a commercial electric noise signal And the analysis of the phenomenon appearing as a common-mode noise is also well known and briefly described.

Hereinafter, the amplifiers G11 and G12, the impedance correcting means 200 and the residual noise canceling means 300, which are characteristic components of the present invention, will be described in detail with reference to FIG.

FIG. 3 is a detailed configuration diagram of a bio-signal measuring apparatus according to an embodiment of the present invention shown in FIG.

3, the electrodes 10 and 20 and the leads 11 and 21 are not shown and instead the electrodes 10 and 20 and the leads 11 and 21 are included Are represented by electrical equivalent circuits.

That is, since the bio-signal extracting unit 100 receives the bio-potential signal through two channels including the electrodes 10 and 20 and the leads 11 and 21, the bio-signal extracting unit 100 expresses the input impedance represented by the two channels.

Here, the input impedances respectively represented by the two channels are determined by the contact impedances of the electrodes 10 and 20 and the human skin, the impedances generated in the leads 11 and 12, The impedance of a filter or an amplifier (not shown) for signal processing before inputting a signal to the bio-signal extracting unit 100. By simplifying the impedance of the filter or the amplifier, serial impedance Z11 and Z21 And can be expressed as parallel impedances (Z12, Z22). The output side of the right leg driving circuit 60 can be expressed as a serial impedance Z31 and a parallel impedance Z32 as well as the lead 31 and the reference electrode 30 connected to the right leg driving circuit 60. [

According to the present invention, even if the input impedance unbalance of two channels occurs, the bio-signals sensed by the electrodes are affected by the input-input impedance and are input to the bio-signal extraction unit 100. The amplifiers G11 and G12, The correction means (200) and the residual noise removing means (300) eliminate the influence of imbalance.

First, the amplifiers G11 and G12 are constituted by an amplifier capable of adjusting the amplification degree by the impedance correcting means 200. The amplifiers G11 and G12 are connected to the positive (+) terminal of the differential operation element G1 for differential operation in the bio- (-) input terminal and the negative input terminal, respectively, before amplifying the bio-potential signals inputted through the two channels into the (+) input terminal and the (-) input terminal of the differential operation element G1, It is possible to do.

For example, the amplifiers G11 and G12 may be constituted by a voltage controlled amplifier (VCA) whose amplification varies according to the magnitude of the DC voltage applied to the control terminal, May be configured to apply a DC voltage for controlling amplification of the amplifiers (G11, G12) to the control terminals of the amplifiers (G11, G12).

Hereinafter, the amplifiers G11 and G12 to be installed in the bio-signal extracting unit 100 will be described before and after they are installed.

First, a description will be given before the amplifiers G11 and G12 are installed.

An ideal case for acquiring a bio-signal is an impedance equilibrium state in which the series impedances Z11 and Z21 are equal to each other and the parallel impedances Z12 and Z22 are equal to each other on the input side of the bio- Similarly, when the impedance equilibrium state is established, the sizes of the common-mode noise input to the bio-signal extracting unit 100 are equal to each other, so that the common-mode noise can be removed by the differential calculation.

However, even if the human body moves a little, impedance impedance equilibrium state in which the series impedance Z11 and Z21 varies according to a change in contact resistance between the electrode and the human body, The impedance equilibrium state is not maintained by the movement of the human body even if the measurement of the biological signal starts. In addition, not only the contact resistance between the electrode and the human body but also the impedance unbalance state can be caused by a characteristic error of the constituent elements constituting each channel.

The influence of the common-mode noise due to the impedance unbalance becomes apparent by the following concrete example.

It is assumed that the series impedance Z11 and Z21 and the parallel impedances Z12 and Z22 are equally constituted by a resistance component or a capacitor component in the same manner without calculating a complex number, The series impedances Z11 and Z21 are set at 100 OMEGA, the parallel impedances Z11 and Z21 are set at 1000 OMEGA, and the amplification factor of the differential operational amplifier G1 is set at 1000. Assuming that the biological signal generated from the human body is 1mV, the common-mode noise can be almost several hundreds to several thousand times that of the biological signal, and therefore, it is assumed that 1000mV, for example. When an impedance imbalance state in which one of the series impedances Z21 is changed from 100? To 110 ?, an undesired signal mixed with a large-value common-mode noise is measured as shown in Table 1 below.

channel Serial
impedance Parallel
impedance Common noise per channel After differential operation amplification
Frost noise residue ch1 Z11
= 100 Ω Z12
= 1000Ω 1000 mV * 1000 / (100 + 1000)
= 909.091 mV (909.091-900.901) * 1000
= 8190 mV ch2 Z21
= 100 + 10
= 110 Ω Z22
= 1000Ω 1000 mV * 1000 / (110 + 1000)
= 900.901 mV

Referring to Table 1, when any one of the series impedances Z21 is increased by 10% to become an impedance unbalance state, the magnitude of the common noise introduced into the bio-signal extracting unit 100 also varies between channels, Since the same phase noise of about 8190 mV is mixed in the biological signal of about 1 V (1000 mV), the common-mode noise appears much larger than the biological signal. As a result, the waveform of the biological signal can not be obtained due to a slight impedance difference between the channels.

In the meantime, according to the embodiment of the present invention, the amplifiers G11 and G12 for amplifying the signals input through the respective channels are provided in the bio-signal extracting unit 100 prior to the differential calculation, G12) are finely adjusted and amplified, it is possible to obtain a signal in which the in-phase noise is suppressed, that is, a signal in which the biological signal to be measured is clearly marked, as shown in Table 2 below.

channel Serial
impedance Parallel
impedance Common noise per channel After amplification with amplifiers G11 and G12
Common noise per channel After differential operation amplification
Frost noise residue  ch1 Z11
= 100 Ω Z12
= 1000Ω 1000mV
* 1000 / (100 + 1000)
= 909.091 mV Gain of G11 = 1
909.091 mV
*One
= 909.091 mV (909.091-909.009)
* 1000
= 81.9 mV ch2 Z21
= 100 + 10
= 110 Ω Z22
= 1000Ω 1000mV
* 1000 / (110 + 1000)
= 900.901 mV Gain of G12 = 1.009
900.901 mV
* 1.009
= 909.009 mV

Referring to Table 2, even if the impedance of the channel becomes unbalanced, since the gain of one of the amplifiers G12 is finely adjusted and amplified so that the two-channel common mode noise inputted to the differential operational amplifier G1 becomes almost the same, , A waveform in which a common mode noise of 81.9 mV is mixed with a biological signal of approximately 1 V (1000 mV) is obtained. As a result, it is possible to obtain a waveform of a signal mixed with a very small phase noise that is much smaller than a biological signal.

In Table 2, in order to make it easier to compare with the results of Table 1, only one of the amplifiers G12 is controlled by gain. However, in the embodiment of the present invention, When the gain is increased, the gain of the other amplifier (G11) is lowered, so that the power fluctuation of the bio-signal obtained after the differential operation hardly occurs.

In this way, the amplification of the amplifiers G11 and G12 provided in the bio-signal extracting unit 100 is adjusted by the impedance correcting unit 200 in order to compensate for the impedance imbalance between the channels.

The impedance correcting means 200 includes a power extracting unit 210 for obtaining the power of the in-phase noise from the signal obtained by the differential calculation by the bio-signal extracting unit 100, A gain control unit 220 for monitoring the power fluctuation of the in-phase noise while finely changing the amplification degree of the amplifiers G11 and G12 to track the gain for reducing the power of the in-phase noise to adjust the amplification degree of the amplifiers G11 and G12, .

Here, the gain controller 220 may change the gain of the amplifiers G11 and G12 by increasing the amplification of one of the two amplifiers G11 and G12 and changing the amplification of the other one of the amplifiers G11 and G12, do.

Therefore, it is preferable to adjust the amplification degree of the amplifiers G11 and G12 to compensate for the impedance imbalance between the channels. Furthermore, since it is desirable to maintain the power of the bio-signal to be acquired even if the amplification degree is adjusted, And at the same time, finds an amplification degree that reduces the power of the common-mode noise while slightly lowering the amplification degree of the other one. At this time, initially, after increasing the amount of change in the amplification degree, gradually changing the amplification degree is made small, and the amplification degree is repeated until the power of the in-phase noise converges to a preset value. If the power of the inphase noise is increased in the state where the amplification degree of either one is increased and the amplification degree of the other is decreased, the amplification degree which reverses the direction of change of the amplification degree is traced so as to reduce the power of the common mode noise.

The power extracting unit 210 may set the power of the in-phase noise signal to the power of the commercial electric frequency component. The power extracting unit 210 extracts the power of the commercial electric frequency component from the signal obtained by performing differential operation on the bio-signal extracting unit 100. The gain controlling unit 220 receives the power of the commercial electric frequency component from the amplifiers G11 and G12 ) To monitor the power of the commercial electrical frequency component and track the amplification that reduces the power of the commercial electrical frequency component. This is because a commercial electrical noise signal is introduced when a biological signal is extracted. For example, in Korea, a component of 60 Hz is regarded as a frost noise, and in Europe, a component of 50 Hz is regarded as a frost noise.

On the other hand, after the in-phase noise signal artificially intended for the human body is applied to the human body through the reference electrode 30 or another third electrode for the right leg drive circuit 60 that negatively feeds the common-mode noise to the human body, And the amplification degree of the amplifiers G11 and G12 may be adjusted by monitoring the common-mode noise signal.

Here, the above-mentioned in-phase noise signal can be applied to various types of signals such as a specific frequency or a specific pattern. When the frequency is a specific frequency, a frequency modulation or a filter such as FFT is used to extract the signal. Can be monitored by extracting the noise size using a correlation analysis technique.

In order to use the intended inphase noise signal, a signal generator (not shown) for generating a specific frequency signal of a frequency band preset by the user or a specific pattern signal of a pattern preset by the user, And a reference electrode 30 or another third electrode for applying a signal to the human body.

When the specific frequency signal is applied to the human body, the power extracting unit 210 extracts the signal power of the predetermined frequency band from the signal obtained by differential operation to the bio-signal extracting unit 100, The control unit 220 monitors the signal power of the preset frequency band while finely adjusting the amplification degree of the amplifiers G11 and G12 and tracks the amplification degree which reduces the signal power of the preset frequency band.

When a specific pattern signal is applied to a human body, a specific pattern signal is sensed through the electrode, processed by the bio-signal extracting unit 100, and then output. The power extracting unit 210 extracts the pattern signal from the bio- And the gain controller 220 controls the gain of the amplifiers G11 and G12 so as to obtain the degree of correlation between the signal obtained by the differential operation and the specific pattern signal applied to the human body, Monitor the resulting value and track the amplification that lowers the correlation. Adjusting the amplification degree to lower the correlation has the same meaning as decreasing the noise power.

On the other hand, the signal of the specific frequency band may not be determined as the in-phase noise, but may be adjusted to an amplification degree for reducing the power of the signal obtained by differential operation with the bio-signal extracting section 100. This method is applicable to a situation in which the impedance unbalance state is severe and the magnitude of the in-phase noise signal appears much larger than the biomedical signal in the signal obtained by performing differential calculation with the bio-signal extracting unit 100. [ That is, when the inphase noise signal is in a very large state, the impedance unbalance can be partially removed by adjusting the amplification degree so that the specific frequency is not extracted but instead the power is reduced.

Although not shown in FIG. 3, for example, a microprocessor (not shown) for processing the power ratio extracting unit 320 and the signal processing unit 50 of the impedance correction unit 200, the residual noise removing unit 300 An analog-to-digital converter is used. In order to adjust the amplification degree of the amplifiers G11 and G12 by the microprocessor, the amplification degree adjusting signal is converted into a digital signal by a D / A converter to-analog converter, and inputs the converted signals to the control terminals of the amplifiers G11 and G12. The component G1 for differential operation of the bio-signal extractor 100 may be constituted by a differential operational amplifier, but it may be constituted by an A / D converter for performing differential calculation to obtain a digital signal. The A / D converter and the D / A converter have been briefly described since they are known technologies that can be installed in the places necessary in the technical field of the present invention.

Amplifiers G11 and G12 are provided in the bio-signal extracting unit 100 for differential operation and the amplification degree of the amplifiers G11 and G12 is adjusted by the impedance correcting unit 200 so that the common- The common-mode noise can be retained without being completely suppressed. That is, as shown in Table 2, if the amplification degree of the amplifiers G11 and G12 is finely adjusted, the common-mode noise is greatly suppressed. Therefore, after suppressing the remaining common-mode noise as much as possible until the magnitude of the residual common-mode noise preset by the impedance correction means 200 is reached, residual noise elimination means 300, which will be described later, is used to suppress the residual common-mode noise.

The residual noise removing unit 300 extracts the in-phase noise signal from the biological signal extracting unit 100 and normalizes the same with the power of the in-phase noise mixed with the signal obtained by the differential calculation by the biological signal extracting unit 100, Is subtracted from a signal obtained by performing differential calculation with the bio-signal extracting unit (100). Thus, the residual noise removing means 300 suppresses the residual common mode noise that is not suppressed by the two amplifiers G11 and G12 and the impedance correcting means 200, thereby acquiring a biomedical signal in which the in- can do.

The remaining noise removing unit 300 for removing noise includes a common noise extraction unit 310 for summing signals amplified by the two amplifiers included in the bio-signal extracting unit 100 to obtain an in-phase noise signal, A power ratio extracting unit 320 for obtaining a ratio of the power of the in-phase noise power of the signal obtained by differential operation to the power of the noise signal to the bio-signal extracting unit 100; And a subtractor 340 for subtracting the normalized in-phase noise signal from a signal obtained by performing differential computation on the normalized in-phase noise signal by the bio-signal extractor 100. The in-

Here, the power ratio extracting unit 320 may extract the in-phase noise obtained by the in-phase noise extracting unit 310 using the processor used in the power extracting unit 210 to obtain the in- And the power of the commercial electric frequency component is obtained from the signal obtained by performing differential operation with the bio-signal extracting unit 100, respectively. This is because a signal obtained by adding signals amplified by the two amplifiers included in the bio-signal extracting unit 100 is also mixed with a noise signal other than a bio-signal or a commercial electric frequency component.

Meanwhile, as described above, a signal of a predetermined frequency band is applied to an electrode, not an electrode for bioelectronic potential measurement, and the in-phase noise signal obtained by the in-phase noise extraction unit 310 and the in- The powers of the predetermined frequency band components may be obtained from the signals obtained by the differential operation to obtain the power ratios.

Of course, the power of a specific frequency (commercial electric frequency component or the predetermined frequency component) can be obtained by extracting the power of a specific frequency band after performing, for example, FFT (Fast Fourier Transform).

When a specific pattern signal is applied to a human body, a correlation between a specific pattern signal to be applied to the human body and the in-phase noise signal obtained by the in-phase noise extraction unit 310 is calculated, After calculating the degree of correlation between the signals obtained by performing the differential operation with the signal extracting unit 100, the ratio of the calculated degree of correlation is used in place of the power ratio.

Thus, by operating the residual noise canceling means 300 after the operation of the impedance correcting means 200, the common-mode noise due to the impedance imbalance of the two channels is suppressed as much as possible, It is possible to obtain a living body signal waveform in which the influx of the living body signal is sufficiently removed.

4 is a detailed configuration diagram of a bio-signal measuring device according to a second embodiment of the present invention.

Referring to FIG. 4, two biological signal extraction units 100 (100-1, 100-2) having amplifiers are provided and the first biological signal extracting unit 100-1 and the second biological signal extracting unit 100-2, and the first and second biological signal extracting units 100-1 and 100-2 are connected in parallel to two channels.

The power extracting unit 210 of the impedance correcting means 200 obtains differential-operated signals from the first biological signal extracting unit 100-1 and the second biological signal extracting unit 100-2, Of power.

The gain adjusting unit 220 adjusts the amplification of either one of the two sets of the biological signal extracting units 100 (100-1, 100-2) so that when the same phase noise becomes smaller than the other one, And the amplification degree of the other amplifier is adjusted by repeating the process of adjusting the amplification degree of the other amplifier with the adjusted state, and when the same phase noise power reaches the predetermined convergence condition, the biosignal obtained from the bio- And transmits it to the residual noise canceling means 300. Here, the switch 230 may be a multiplexer (MUX).

At this time, the predetermined convergence condition may be a condition that the in-phase noise power is lowered to a predetermined value or less, or a ratio or degree of the phase noise power is gradually reduced even if the amplification degree is adjusted, As shown in FIG.

The amplification degree of the amplifiers G11 and G12 of the first biological signal extracting section 100-1 and the amplification degree of the amplifiers G21 and G22 of the second biological signal extracting section 100-2 Phase noise obtained by the differential operation in the same state is compared with each other, and then the bio-signal extracting unit into which the smaller common-mode noise flows is selected. For example, if the common-mode noise of the first biological signal extracting unit 100-1 is smaller, the amplification degree of the amplifiers G21 and G22 of the second biological signal extracting unit 100-2 is changed, It is monitored whether the same phase noise becomes smaller than the extraction unit 100-1. Here, as described above, one of the amplifiers G21 and G22 is amplified and the other is amplified.

Next, when the amplitudes of the amplifiers G21 and G22 of the second living body signal extracting unit 100-2 are changed so that the same phase noise becomes smaller than that of the first living body signal extracting unit 100-1, The amplification degree of the amplifiers G11 and G12 of the first living body signal extracting unit 100-1 is changed to monitor whether the same phase noise is smaller than the second living body signal extracting unit 100-2. Here, after the amplitudes of the amplifiers G11 and G12 of the first biological signal extracting unit 100-1 are adjusted to the adjusted amplitudes of the amplifiers G21 and G22 of the second biological signal extracting unit 100-2, . This is the point at which it starts to change the amplification, even though it is for the other amplifier.

While the amplifiers G11 and G12 of the first living body signal extracting unit 100-1 and the amplifiers G21 and G22 of the second living body signal extracting unit 100-2 are alternately controlled as described above, When the condition is reached, the switch 230 finally selects the bio-signal obtained from any one of the bio-signal extraction units having a relatively small common mode noise power mixed with the signal obtained by the differential operation. Of course, if the impedance difference is changed, the above process is repeated to select one of the two sets of bio-signal extractors as the switch 230 again.

The residual noise removing unit 300 receives the signals amplified by the amplifiers from the two sets of the biological signal extracting units 100 (100-1 and 100-2), selects the received signal as a signal for obtaining the in-phase noise signal And a multiplexer (MUX) Since the impedance correcting means 200 has selected one of the two sets of the biological signal extracting units 100 (100-1 and 100-2) as the switch 230, the multiplexer (MUX) It is preferable that a signal is received from the biological signal extracting unit selected by the biological signal extracting unit 230 to obtain the in-phase noise signal. The operation of the power ratio extracting unit 320, the inphase noise normalizing unit 330 and the subtracting unit 340 using the signal selected by the multiplexer 350 is the same as that of the first embodiment of the present invention And thus redundant description is omitted.

Since the embodiment shown in the drawing has the right leg driving circuit 60, it can obtain a noise signal to be negatively fed back to the human body from a signal selected by the multiplexer (MUX) 350, and a separate multiplexer a multiplexer may be provided to receive a signal from the biological signal extracting unit selected by the switch 230 to obtain an operation noise signal to be negatively fed back to the human body.

5 is a detailed configuration diagram of a bio-signal measuring apparatus according to a third embodiment of the present invention.

5, the bio-signal measuring apparatus according to the third embodiment of the present invention includes two sets of bio-signal extractors 100 (100-1 and 100-2) in the same manner as the second embodiment, The biometric signal extraction unit 100 (100-1, 100-2) is alternately controlled by the correction means 200 and the amplification degree of the amplifier is controlled to select the biometric signal extraction unit having relatively small in-phase noise. However, The biometric signal extracting unit is selected using the multiplexer 230 'instead of the biometric signal extracting unit 230.

The residual noise removing unit 300 may be configured to remove the in-phase noise extracting unit 310 of the first and second embodiments and instead of the two sets of the biological signal extracting units 100 (100-1, 100-2) And obtains the in-phase noise signal using the bio-signal extractor not selected as the multiplexer 230 '.

More specifically, the gain adjusting unit 220 of the impedance correcting unit 200 adjusts the amplification degree of the amplifier by alternately switching the two sets of the biological signal extracting units 100 (100-1 and 100-2) And then selects one of the two amplifiers of the non-selected bio-signal extractor to reverse-amplify the amplified signal or to block the output of the amplified signal (the gain is set to 0 ). Then, the signal obtained by the differential operation in the non-selected biological signal extraction unit is a signal in which the in-phase noise predominates, that is, the biological signal to be measured is mixed but the phase noise is mixed with the signal which is much larger than the biological signal.

The multipather 230 'selects a biomedical signal extractor having a small in-phase noise and outputs an output of another biomedical signal extractor which is not selected at this time to the in-phase noise normalizer 330 As shown in FIG.

The power ratio extracting unit 320 calculates the powers of the in-phase noise bands from the signals output from the two sets of the biological signal extracting units 100 (100-1, 100-2), respectively, (Signal obtained by compensating impedance imbalance between channels to suppress in-phase noise) of the in-phase noise band power mixed in the output signal of the bio-signal extracting unit (the signal of the in-phase noise band that is not selected by the multiplexer 230 ' Phase noise band power mixed in a signal with a very high noise level), and reflects the calculated power ratio to the in-phase noise normalization unit 330.

Accordingly, the normalized in-phase noise can be obtained by the in-phase noise normalization unit 330, and the in-phase noise remaining in the output signal of the biological signal extraction unit selected by the multiplexer 230 'can be suppressed by the subtraction unit 340 have. In the third embodiment shown in FIG. 5, the operations of the power ratio extracting unit 320, the in-phase noise normalizing unit 330, and the subtracting unit 340 are the same as those of the first and second embodiments, .

Since the right leg driving circuit 60 is also provided in the third embodiment shown in Fig. 5, a multiplexer for selecting any one of the two sets of the biological signal extracting units 100 (100-1, 100-2) (61).

The third embodiment having such a structure has an advantage that the residual noise removing means 300 is simplified as compared with the second embodiment. Of course, the impedance correcting means 200 and the residual noise canceling means 300 may also be constituted by one microprocessor, and the processor for obtaining the in-phase noise power used by the power extracting unit 210 may be referred to as a power ratio extracting unit 320 ).

6 is a detailed configuration diagram of a bio-signal measuring device according to a fourth embodiment of the present invention.

According to the fourth embodiment of the present invention, the bio-signal extracting unit 100 amplifies the bio-potential signals for each channel input through the two channels (ch1 and ch2) composed of the electrode and the lead by the amplifiers, A first preprocessing unit 110 and a second preprocessing unit 120 that acquire independently preprocessed signals and a preprocessed signal obtained independently by the first preprocessing unit 110 and the second preprocessing unit 120, And a differential arithmetic unit 130 for performing a differential arithmetic operation on the power normalized so that the powers of the same phase noise are the same and acquiring a bio-signal suppressing the in-phase noise.

The impedance correcting means 200 simultaneously adjusts the amplification degree of the amplifiers provided for the respective channels in the two preprocessing units composed of the first preprocessing unit 110 and the second preprocessing unit 120, Trace amplification is controlled so that the common mode noise power mixed with the acquired bio signal becomes smaller.

First, the first preprocessing unit 110 and the second preprocessing unit 120 are connected in parallel to the channels ch1 and ch2. The respective channels are connected to the (+) input terminal of the differential arithmetic unit of one of the preprocessing units, It is connected to the (-) input of the differential operator of one preprocessor.

More specifically, the differential arithmetic units G1 and G2 provided in the first preprocessing unit 110 and the second preprocessing unit 120 are configured to perform differential computation on signals input to the (+) input terminal and the (- A channel ch1 is branched and connected to the first preprocessing unit 110 and the second preprocessing unit 120. The first preprocessing unit 110 is connected to the differential calculator G1 and is connected to the (-) input terminal of the differential computing unit G2 via the amplifier G22 in the second preprocessing unit 120. [

The other channel (ch2) branches to be connected to the remaining input terminals of the differential arithmetic unit via the amplifiers in the first preprocessing unit 110 and the second preprocessing unit 120, respectively. That is, the other channel ch2 is connected to the (-) input terminal of the differential computing unit G1 via the amplifier G12 in the first preprocessing unit 110, ) To the (+) input terminal of the differential operator G2.

In other words, the input terminal polarity of the differential operator G1 of the first preprocessor 110 and the input terminal polarity of the differential operator G2 of the second preprocessor 120 are changed.

By connecting the first preprocessing unit 110 and the second preprocessing unit 120 to the channels ch1 and ch2 in this manner, the in-phase noise components in the bioelectrical potential signal introduced through the two channels ch1 and ch2 1 pre-processing unit 110 and the second pre-processing unit 120, the noise components after being pre-processed by the first pre-processing unit 110 and the noise components after being pre-processed by the second pre-processing unit 120 are amplified by the amplifiers G11 , G12, G21, G22), or they may be in phase.

However, if any one of the input terminal polarities of the differential operators (G1, G2) is designated in advance and the ratio between the amplification degree of the amplifier connected to the input terminal of the designated polarity and the amplification degree of the amplifier connected to the other polarity is set as the common- The noise component signals mixed in the signal preprocessed by the first preprocessing unit 110 and the second preprocessing unit 120 become the same phase.

6, the ratio of amplification of the amplifier G11 to the amplifier G12 in the first preprocessing unit 110 and the amplification ratio of the amplifier G21 to the amplifier G22 in the second preprocessing unit 120 are The noise component signals mixed in the signals pre-processed by the first preprocessing unit 110 and the second preprocessing unit 120 become the same phase if the power ratio of the in-phase noise signal flowing through the channels ch1 and ch2 is greater than the power ratio of the in-

In this case, when the signal pre-processed by the first preprocessing unit 110 and the second preprocessing unit 120 is differentially computed by the differential arithmetic unit 130, the in-phase noise signal is suppressed.

Therefore, if the impedance of the first preprocessing unit 110 and the second preprocessing unit 120 is adjusted so that the in-phase noise is reduced in the signal obtained by the differential operation unit 130, Converges to have a ratio between the degree of amplification under the condition that the in-phase noise signal is suppressed as described above.

In the embodiment of the present invention, in order to more quickly track the amplification degree of the amplifiers provided in the first preprocessing unit 110 and the second preprocessing unit 120, the preprocessing units 110 and 120 One of the input terminal polarities is designated in advance and the amplification degree is adjusted while the amplification degree of the amplifier connected to the input of the specified polarity is made larger than the amplification degree of the amplifier connected to the other polarity. For example, the amplifiers G11 and G21 provided at the (+) input terminals of the differential operators G1 and G2 are connected to the amplifiers G12 and G22 provided at the (-) input terminal of the differential calculators G1 and G2, The amplification degree is finely adjusted and the amplification degree tracking process is performed.

On the other hand, during the process of tracking the amplification degree as described above, the bio-potentials flowing through the two channels (ch1 and ch2) by the arrangement (positions attached to the human body) of the electrodes 10 and 20 for obtaining the bio- Even if the biosignal component, which is a reverse phase signal, passes through the first preprocessing unit 110 and the second preprocessing unit 120, the biosignal component after the preprocessing in the first preprocessing unit 110 and the biosignal component in the second preprocessing unit 120, The in vivo signal component after the preprocessing is reverse-phase.

Therefore, the reverse-phase biomedical signal mixed with the signal obtained by the preprocessing can be obtained as a biomedical signal having sufficient power without being suppressed even when the differential operation unit 130 performs differential operation.

6, the differential arithmetic unit 130 amplifies signals obtained by preprocessing by the first preprocessing unit 110 and the second preprocessing unit 120 with amplifiers G31 and G32, respectively, (G3), and the amplification degree of each of the amplifiers G31 and G32 is adjusted by the power normalization unit 131. [

That is, the power normalization unit 131 extracts the power of the in-phase noise component signal from a signal obtained by being pre-processed by the first preprocessing unit 110 and the second preprocessing unit 120, and the power of the first preprocessing unit 110 ) And the amplification degree of the amplifiers G31 and G32 are adjusted so that the powers of the in-phase noise component signals mixed in the signals obtained by the preprocessing by the second preprocessing unit 120 become equal. Here, amplification of any one of the two amplifiers G31 and G32 may be adjusted so that the power of the in-phase noise component signal may be the same.

Accordingly, the signals input to the (+) input terminal and the (-) input terminal of the differential operator G3 have the same powers of the in-phase noise signals, so that the common mode noise is suppressed by the differential operation of the differential operator G3 Signal, that is, a signal in which a biomedical signal to suppress and obtain a common-mode noise is sufficiently large is acquired. Here, since the power of the in-phase noise signal becomes the same because there are factors such as an error that occurs in the extraction of the in-phase noise power, the fact that the same phase noise can be suppressed to a desired level by the differential operation of the differential operator G3 .

In this way, the amplification of the amplifiers G11 and G12 of the first preprocessing unit 110 and the amplification of the second amplifiers G11 and G12 of the first preprocessing unit 110 are minimized so that the common mode noise is minimized in the signals obtained by the differential operation with the differential operation unit 130 having the power normalization unit 131. [ By adjusting the amplification of the amplifiers G21 and G22 of the preprocessing unit 120, it is possible to obtain a bio-signal suppressing the common-mode noise even if the impedance imbalance between channels occurs, and the amplification is also controlled by the power normalization unit 131. [ (G31, G32), and then the in-phase noise power is substantially the same. Thus, in the fourth embodiment of the present invention, the residual noise removing means 300 of the first, second, and third embodiments of the present invention may not be provided.

Meanwhile, the common mode noise power extraction required for the normalization in the power normalization section 131 and the common mode noise power extraction required for the tracking of the amplification degree in the impedance correction means 200 are the same as the first and second and third embodiments The signal power extraction of a preset frequency band after applying a signal of a predetermined frequency band, and a signal of a specific pattern which is set in advance after applying a predetermined specific pattern signal to the human body, And power extraction. Here, when the signal power of a predetermined pattern is extracted in advance, the impedance correction unit 200 adjusts the amplification degree so that the degree of correlation becomes smaller as in the first, second, and third embodiments of the present invention, The amplification degree of the amplifiers G31 and G32 is adjusted so that the degree of correlation with a specific pattern signal set in advance for the signal obtained by differential operation in the preprocessing units 110 and 120 respectively and the correlation is the same.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, . ≪ / RTI > Accordingly, such modifications are deemed to be within the scope of the present invention, and the scope of the present invention should be determined by the following claims.

Z11, Z21: Serial impedance Z12, Z22: Parallel impedance
G1, G2, G3: Differential operator
G11.G12, G21, G22, G31, G32: Amplifier
10, 20: electrodes 11, 21: conductors
30: reference electrode 40: biological signal extracting unit (prior art)
50: signal processing section 60: right leg drive circuit
100: biological signal extracting unit (present invention)
110, 120: preprocessing unit 130: differential operation unit
200: Impedance correction means
210: power extracting unit 220: gain adjusting unit
300: Residual noise removing means
310: common noise extraction unit 320: power ratio extraction unit
330: In-phase noise normalization unit 340:

Claims (14)

Two channels for detecting the bioelectrical potential of each human body by the two electrodes 10 and 20;
A bio-signal extracting unit (100) for acquiring a bio-signal by amplifying the bio-potentials input through the two channels by an amplifier and performing differential operation with a differential operator to suppress the in-phase noise;
An impedance correcting means 200 for adjusting the amplification degree of the amplifier so that the power of the in-phase noise mixed in the bio-signal acquired by the bio-signal extracting unit 100 is reduced to suppress the in-phase noise due to the impedance unbalance between the channels;
Wherein the bio-signal measuring device comprises: The method according to claim 1,
The impedance correction means (200)
The power of the common mode noise mixed in the biological signal acquired by the biological signal extraction unit 100 while increasing the amplification of one of the two amplifiers provided for each channel and lowering the amplification of the other, The amplitude of the amplifier is tracked and adjusted. 3. The method of claim 2,
The bio-signal extracting unit 100 is provided in two and connected in parallel to a channel,
The impedance correction means (200)
When the common-mode noise becomes smaller than that of the other biological signal extracting unit by adjusting the amplification degree of one of the biological signal extracting units, the amplification of one of the biological signal extracting units is adjusted and the amplification of the other one of the biological signal extracting units Wherein the process of adjusting the amplification degree is repeated to adopt the biological signal acquired from the biological signal extracting unit in which the in-phase noise is relatively small in the two biological signal extracting units. The method of claim 3,
The impedance correction means (200)
When the common-mode noise becomes smaller than that of the other biological signal extracting unit by adjusting the amplification degree of the biological signal extracting unit of one of the biological signals, after adjusting the amplification degree of the other biological signal extracting unit to the adjusted amplification degree of the biological signal extracting unit And starts to change the amplification degree of the amplifier of the other bio-signal extracting unit. The method according to any one of claims 1 to 4,
The in-phase noise signal is obtained by summing the signals amplified by the two amplifiers included in the bio-signal extracting unit 100 to obtain the in-phase noise signal. The in- And residual noise removing means (300) for subtracting the signal obtained by the normalization by the power of noise and the signal acquired by the biological signal extracting unit (100) to acquire a living body signal suppressing the residual common mode noise. Biological signal measuring device. 6. The method of claim 5,
The residual noise canceling means 300
Wherein the in-phase noise signal is multiplied by the ratio of the in-phase noise power of the signal obtained by performing differential operation on the power of the obtained in-phase noise signal to the bio-signal extracting unit (100), thereby normalizing the in-phase noise signal. The method according to claim 6,
Wherein the residual noise canceling means (300) is activated after the operation of the impedance correcting means (200) to suppress the residual common mode noise after suppressing the common mode noise due to the impedance unbalance between the channels, . The method according to claim 6,
The impedance correcting means 200 tracks and adjusts the amplification degree of the amplifier so that the power of the commercial electric frequency component becomes smaller in the signal acquired by the bio-signal extracting unit 100,
Wherein the ratio of power for normalization in the residual noise removing unit (300) is a ratio of power to a commercial electric frequency component. The method according to claim 6,
A signal of a predetermined frequency band is applied to a human body through an electrode, not an electrode for measuring a bioelectrical potential,
The impedance correcting means 200 tracks and adjusts the amplification degree of the amplifier so that the power of the predetermined frequency band becomes smaller in a signal acquired by the bio-signal extracting unit 100,
Wherein the ratio of power for normalization in the residual noise removing unit (300) is a ratio of power to the predetermined frequency band component. The method according to claim 6,
A signal of a predetermined pattern set in advance to the human body is applied to the human body via an electrode, not an electrode for measuring the bioelectrical potential,
The impedance correcting means 200 adjusts the amplification degree of the amplifier so that the degree of correlation between the signal obtained by the bio-signal extracting unit 100 and the predetermined pattern signal to be applied to the human body is reduced,
Wherein the ratio of the power for normalization in the residual noise removing means (300) is a correlation degree with the signal of the predetermined pattern to be applied to the human body. The method according to claim 1,
The bio-signal extracting unit (100)
Two pairs of preprocessing units 110 and 120 for performing differential computation on a bioelectrical potential signal input to two channels by an amplifier and then performing a differential computation on the bioelectrical potential signals are connected in parallel, and each channel is connected in parallel by a differential computing unit of one of the preprocessing units (-) input terminal of the other preprocessing unit and connected to the (-) input terminal of the other preprocessing unit, and a differential operation unit 130 for performing differential operation on the signals obtained by the two sets of preprocessing units 110 and 120 to acquire biological signals, Further comprising:
The impedance correction means (200)
And extracts the in-phase noise power mixed with the bio-signals acquired by the differential arithmetic operation unit 130 to adjust the amplification degree of the amplifiers provided for the respective channels in the two preprocessing units 110 and 120 so that the in- A living body signal measuring device. 12. The method of claim 11,
The differential operation unit 130
The in-phase noise power is extracted from the signals obtained by the two preprocessing units 110 and 120. The in-phase noise power is normalized so that the in-phase noise power mixed in the signals obtained by the two sets of preprocessing units 110 and 120 becomes equal, And acquires a signal from the biological signal. 13. The method of claim 12,
The impedance correction means (200)
In order to adjust the amplification degree of the amplifiers provided in the two sets of preprocessing units 110 and 120, one of the input terminal poles of the pre-processing units 110 and 120 is pre-specified, Wherein the amplification degree is controlled by increasing the amplification degree of the amplifier connected to the input terminal of the other polarity than the amplification degree of the amplifier connected to the input terminal of the other polarity. The method according to claim 12 or 13,
The common-mode noise power extracted by the impedance correcting means 200 and the common-mode noise power extracted by the differential arithmetic operation unit 130 are determined by the power of the commercial electric frequency component, the signal power of a predetermined frequency band applied to the human body, And a signal power of a predetermined pattern that is set in advance.

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